The results appear in this week's issue of the Proceedings of the National Academy of Sciences.

Researchers are currently working to map the origins of the remaining 28 artifacts.

"Archaeologists have noticed the jade artifacts had similar styles and shapes" across different Asian regions since the 1940s, said lead study author Hsiao-Chun Hung, also at ANU.

"But we never thought it was from the same source until we tested it."

So far only a single jade earring similar to those used for the study has been found in Taiwan.

But samples from Vietnam and Thailand include cast-off pieces and incomplete earrings found at what scientists believe are workshop sites.

In addition, jade is a very hard mineral, so crafters would need sophisticated carving skills and tools to shape such ornate items.

Only a few highly skilled craftsmen would have the expertise, Bellwood said.

Most likely, these craftsmen exported the jade as a raw material and then manufactured it into jewelry locally, Bellwood said.

"The jade comes from Taiwan, but a lot of artifacts are not made in Taiwan."

Nuanced Understanding

The study is "an important contribution to a matter that deserves more attention: the navigational skills of early Southeast Asian societies," said anthropologist Charles Higham of the University of Otago in New Zealand.

Experts often focus too much on the influence that Chinese and Indian populations had on the cultural advances of Southeast Asian societies, he said.

"Ancestors of the Southeast Asian people were able to cross into Australia over 40,000 years ago over open sea with no land visible, so why were they not also capable of sailing to India and back to trade?" he said.

"This paper illustrates that such movement was possible."

Archaeologist Miriam Stark of the University of Hawaii at Manoa said she is cautiously optimistic about the research.

"This study provides an important springboard for studying chemical compositional sources within Southeast Asia," she said.

"Chemical patterning provides some of the first empirical evidence for a South China Sea interactional network."

Mapping the sources of jade artifacts, she said, is therefore "essential to develop a more nuanced understanding of political economies and social networks in the ancient Southeast Asian world."